WikiLeaks said it planned to release from Monday over 5 million emails from Stratfor Global Intelligence, a provider of geopolitical analysis, whose website was hacked and emails and customer data stolen in December.

The whistle blower site said the emails date from between July, 2004 and late December, 2011, and allegedly contain privileged information about the US government's attacks against WikiLeaks and its founder Julian Assange and Stratfor's own attempts to subvert WikiLeaks. They also allegedly reveal controversial practices by Stratfor in cultivating sources, and targeting of individuals for corporate and government clients, WikiLeaks said.

Stratfor in Austin, Texas said in a statement Monday that mails stolen during the December hack apparently will be published by WikiLeaks. "This is a deplorable, unfortunate -- and illegal -- breach of privacy," it said. "Some of the emails may be forged or altered to include inaccuracies; some may be authentic. We will not validate either".

WikiLeaks did not disclose its source for the emails it is leaking to over 25 media outlets and activists. Hacker group, Anonymous however said in a Twitter message that it gave the Stratfor emails to WikiLeaks. Transparency, whether forced or voluntary, is a necessity to understand our world, it said.

In the long-term the two antiestablishment organizations could collaborate on collection of information, with WikiLeaks handling its distribution through media partners, according to analysts.

Assange declined to discuss whether the Stratfor emails had been stolen as part of the December hack. "We are a source protection organization," he told reporters in London at a streamed news conference. "As a source protection organization, and in fact simply as a media organization, as a matter of policy, we don't discuss sourcing, or speculate on sourcing," he said. WikiLeaks tries not to know where the information comes from, as the strongest protection for a source, he added.

The sourcing and publishing by WikiLeaks is protected as it is for other media organizations under the First Amendment in the U.S., and in some other countries under Article 19 of the U.N. Universal Declaration of Human Rights, Assange added.

Stratfor said in January that it got an alert in December that its website had been hacked and customer credit card and other information had been stolen by Anonymous. Its website was hacked again on Dec. 24.

Stratfor denied the hackers' claim that the data was a list of "private clients" but rather a list of members who may have purchased a publication.

"As one person said, the credit cards were extra, something they took when they realized they could. It was our email they were after," George Friedman, CEO of Stratfor said in the statement in January.

Within Anonymous there were some hackers in December who were opposed to the hacking of Stratfor.